Known vacuum interrupters can be used in medium-voltage circuit breakers for high current interruption at occasional short circuit current fault, as well as for load current switching. For high current interruption, the vacuum arc becomes constricted, and releases very high thermal energy onto the contacts. If not prevented, the arc energy yields a strong local overheating of the contacts, which leads to severe contact erosion and high metal vapor density after zero current, which makes the current interruption very challenging or unsuccessful.
In order to achieve high current interruption performance, the heat arising from the vacuum arc should be managed by spreading out the energy over the whole contacts surface. There can be currently two standard methods for the vacuum arc control in a way to distribute the heat flow over an area of the contacts as large as possible.
The vacuum arc control can be achieved by generating either a transverse magnetic field (TMF) in order to drive the constricted arc in rotating motion under the effect of Lorentz forces, or an axial magnetic field (AMF) to confine the charged particles around the magnetic flux lines and to stabilize the arc by making it diffuse over the whole contact surface with low current density.